QEMU/Monitor

When QEMU is running, it provides a monitor console for interacting with QEMU. Through various commands, the monitor allows you to inspect the running guest OS, change removable media and USB devices, take screenshots and audio grabs, and control various aspects of the virtual machine.

The monitor is accessed from within QEMU by holding down the Ctrl and Alt keys (or whatever the "mouse grab" keystrokes are), and pressing Shift-2. Once in the monitor, Shift-1 switches back to the guest OS. Typing help or ? in the monitor brings up a list of all commands. Alternatively the monitor can be redirected to using the -monitor <dev> command line option. Using -monitor stdio will send the monitor to the standard output, this is most useful when using qemu on the command line.

With no arguments, the help command lists all commands available. For more detail about another command, type help command, e.g.

(qemu) help info

On a small screen / VM window, the list of commands will scroll off the screen too quickly to let you read them. To scroll back and forth so that you can read the whole list, hold down the control key and press Page Up and Page Down.

Print (or p), evaluates and prints the expression given to it. The result will be printed in hexadecimal, but decimal can also be used in the expression. If the result overflows it will wrap around. To use a the value in a CPU register use $<register name>. The name of the register should be lower case. You can see registers with the info registers command.